Conventionally, various types of bonding agents are used in the methods employed for prevention of pile fiber fall-out in pile fabrics. For example, emulsions of synthetic rubber or acrylic acid esters have been widely used, as electrostatic flocking binders and as binders for the backing of napped fabrics such as tufted fabrics and sliver knitting.
Although such water-based emulsions are easy to use, there are certain problems with their resistance to hot water and solvents. They usually cannot be relied upon during the dyeing process, and, moreover, there are several problems concerning durability as a result of dry-cleaning processes which employ solvents such as perchloroethylene (perchlene) and the like.
In addition, in order to obtain super-fine pile fabrics, the so-called "islands-in-sea" type of composite fiber has been tried as a component in recent years. In such cases, bonding agents are usually used prior to the treatment for making the pile super-fine, and these must of necessity be resistant to the process for removal of the sea component. In other words, the ability to withstand a solvent (such as trichloroethylene or xylene) for the dissolution of the sea component or a chemical (such as alkali) for the decomposition of the sea component, is necessary.
Another requirement is for the bonding agent to resist the hot water and the rubbing actions which are used in the dyeing process.
For example, U.S. Pat. No. 3,865,678 and Canadian Pat. No. 895,611 and others refer to examples of electrostatic flocking of island-in-sea fibers. The binder used in examples such as these must be able to withstand the process for removal of the sea component and the dyeing process (100.degree. C.-130.degree. C.), while maintaining its binding strength.
Experiments conducted by us indicate that there are problems concerning the lack of ability not only of various types of bonding emulsions, but also of solutions of acrylic resins and urethane resins, and the inability to withstand high-temperature (120.degree.-130.degree. C.) dyeing treatments (especially jet-dyeing equipment which employs a strong rubbing action) and solvent treatments such as perchloroethylene, or trichloroethylene and the like. On the other hand, heat curable resins is not practical because of their hardness.